IGES to STL Converter

Turn IGES (.iges, .igs) CAD files into STL for printing, meshed in your browser with OpenCascade, with a check for the gaps IGES surfaces often leave.

  • Files stay on your device
  • Free, no sign-up
  • Units and up axis handled
  • Batch and .zip

Drop an IGES file to convert

One file, many, or a .zip

In: STL · STEP · IGES · OBJ · 3MF · GLB · glTF · PLY · FBX · DAE · 3DS · AMF · VRML · ZIP

Converted on your device. Nothing is uploaded.

    How to convert IGES to STL

    1. Drop your IGES files

      Drop .iges or .igs files. The CAD reader (about 7 MB) downloads the first time.

    2. Check the preview

      The model appears at the size and orientation it will have. Fix the file units, up axis or size under Size, units and orientation if needed.

    3. Choose STL options

      Binary STL by default (smallest, read everywhere). Tick ASCII only if an old tool asks for text STL.

    4. Convert and download

      One file downloads straight away. A batch gives a download per file and one .zip of all of them.

    What carries over from IGES to STL

    Worked out from what each format can store and what this converter writes. Nothing is changed silently: the preview shows the size and orientation before you download.

    Geometry Exact IGES surfaces are tessellated into triangles with OpenCascade at the quality you pick (Draft, Normal or Fine).
    Color Dropped: STL cannot store color.
    Units Converted from the declared unit to millimetres, so it keeps its real size.
    Orientation Both are Z up, so it stays the right way up.
    Objects Merged into one surface: STL has no objects.
    Editability Feature history and exact surfaces are not recoverable from a mesh. Keep the CAD file as your master.

    IGES to STL: what actually happens

    IGES often stores surfaces rather than solids: faces that look closed but don't share edges. The converter meshes every surface with OpenCascade and writes them into one STL in millimetres. If the surfaces didn't close, the STL has open edges where they meet.

    Open the result in the STL viewer to check: zero open edges means it will slice cleanly. If not, sew the surfaces in your CAD tool, or try Mesh Repair on the STL.

    IGES at a glance

    Initial Graphics Exchange Specification · .iges, .igs

    Stores
    Curves and trimmed surfaces, sometimes solids
    Color
    Per entity, rarely used
    Units
    Declared in the file
    Up axis
    Usually Z
    Meshing
    Needs tessellation; surface models may not close into solids
    Opens in
    Most CAD and CAM systems

    IGES was first published in 1980 and is still the lowest common denominator between CAD and CAM systems. It often carries loose surfaces rather than closed solids.

    Open IGES files in the viewer

    STL at a glance

    Stereolithography (Standard Triangle Language) · .stl

    Stores
    Loose triangles: three corners and a normal each, binary or ASCII
    Color
    None in the standard
    Units
    None written; slicers assume millimetres
    Up axis
    Z, the slicer convention
    File size
    50 bytes per triangle in binary, about 5 times that as ASCII
    Opens in
    Every slicer, CAD tool and 3D app

    Created by 3D Systems in 1987 for the first stereolithography printers, STL is still the format every slicer and print service accepts. It describes a surface as a list of independent triangles, with no shared vertices, units, colors or scene structure.

    Open STL files in the viewer

    Tips for IGES to STL

    Ask for STEP

    If whoever sent the IGES can export STEP, ask. STEP keeps solids, and STEP to STL gives a cleaner mesh.

    Quality

    Use Fine for small details; Draft for big surface models you only need to check.

    Units

    IGES declares its unit, and the STL comes out in millimetres.

    IGES to STL FAQ

    Can I convert IGS to STL too?
    Yes. .igs and .iges are the same format.

    Why does my STL from IGES have holes?
    The IGES surfaces only appear to meet. Sewing them into a solid in CAD fixes the cause; Mesh Repair can close small gaps.

    Is my file uploaded?
    No. OpenCascade runs in your browser as WebAssembly.

    Is the converter free? Are there limits?
    Free, with no sign-up, watermark or file count limit. Batches and files of a few hundred MB work on most laptops; the only limit is your device's memory.

    Are my files uploaded?
    No. Files are read and written by JavaScript and WebAssembly in your browser and never sent to PrintPal. The STEP and IGES reader is the only extra download, once, from a public CDN.